Reminduck (flatpak):
If you just need a non-complex reminder app with daily, weekly, monthly, and repeating options, this will work. It just needs to be scaled down a little.
Unfortunately, despite promising to quack like a duck, it doesn’t actually walk the talk. There was no auditory notification. (Very disappointed… hhhhhhhhh… 
)
It did trigger the blinking blue LED, though, and as you can see, the printed notification was there. That may be enough for most situations.
(I did verify this app was set for sound & vibration in the L5 Notifications settings, and that the system sounds were up, but it didn’t help.)